On Tue, Feb 06, 2018 at 12:21:15AM +0100, Boris Brezillon wrote:

> +	/*
> +	 * The controller can implement only the high-level SPI-memory like
> +	 * operations if it does not support regular SPI transfers.
> +	 */
> +	if (ctlr->mem_ops) {
> +		if (!ctlr->mem_ops->supports_op ||
> +		    !ctlr->mem_ops->exec_op)
> +			return -EINVAL;
> +	} else if (!ctlr->transfer && !ctlr->transfer_one &&
> +		   !ctlr->transfer_one_message) {
> +		return -EINVAL;
> +	}

BTW your comment isn't describing what the code does - the comment says
that having the memory operations means the driver can't be a regular
SPI controller while the code does not do that and only checks that if a
driver has memory ops it implements two required ones.  Indeed the
existing drivers that are updated to the new API continue to implement
normal SPI operations.